Plum tree named ‘Suplumtwentyeight’

ABSTRACT

A new and distinct plum variety that possesses heavy and consistent production of large, firm, black skinned, early-ripening fruit of excellent eating quality. The juicy flesh develops a red color upon ripening.

Latin name of the genus and species of the plant claimed: Prunussalicina.

Variety denomination: ‘Suplumtwentyeight’.

BACKGROUND AND SUMMARY OF THE INVENTION

This invention relates to the discovery and asexual propagation of a newand distinct variety of plum tree, herein after referred to by thecultivar name ‘Suplumtwentyeight’. The variety originated byhybridization performed by Bruce Mowrey. The new variety was firstselected and evaluated by David Cain on Sun World Experimental Ranch 75near Wasco, Calif. in Kern County. The new variety is characterized byheavy and consistent production of large (65 mm diameter), firm fruitthat ripens early, during the middle of June in the Bakersfield, Calif.area. Fruit of ‘Suplumtwentyeight’ have smooth black-colored skin andflesh that develops red color as they ripen. Eating quality is excellentwith 18° brix, plentiful juice, and skin flavor that is neutral.

The parent varieties were first crossed in 1993, with the date ofplanting of February, 1994, and the date of first flowering being March,1997. The new plum variety was first asexually propagated by Terry Baconnear Wasco, Kern County, Calif. in December, 2001, by grafting ontoNemaguard rootstock.

The seed parent is Sun World breeding selection, ‘91P-001’ (unpatented),which was selected from a progeny of Sun World breeding selection‘232-205’ (unpatented) crossed with pollen from Sun World selection‘275- 136’ (unpatented). The new variety is distinguished from its seedparent by ripening 16 days later and having fruit that averages 65 mm ascompared to ‘91P-001’ with 55 mm. Additionally, the new variety developsred flesh as it ripens while ‘91P-001’ has amber flesh. The pollenparent was an unknown Sun World breeding selection.

The new variety most nearly resembles ‘Suplumeleven’ (U.S. Plant Pat.No. 4,902). It may be distinguished from ‘Suplumeleven’ by ripening 20days earlier. The new variety ripens approximately the same time as‘Santa Rosa’ (unpatented) but develops red flesh while ‘Santa Rosa’ hasamber-colored flesh, and is larger (65 mm compared to 55 mm diameterwith ‘Santa Rosa’).

The new plum tree variety cv. ‘Suplumtwentyeight’ has been shown tomaintain its distinguishing characteristics.

BRIEF DESCRIPTION OF THE FIGURE

The accompanying color photographic illustration in FIG. 1 shows typicalspecimens of the foliage and fruit of the new plum variety. Theillustration shows the upper and lower surface of the leaves, anexterior and sectional view of a fruit divided across its suture planeto show flesh color, pit cavity and the stone remaining in place. Thephotographic illustration was taken shortly after being picked (shippingripe) and the colors are as nearly true as is reasonably possible in acolor representation of this type.

DETAILED BOTANICAL DESCRIPTION OF THE INVENTION

Throughout this specification, color names beginning with a small lettersignify that the name of that color, as used in common speech, is aptlydescriptive. Color names beginning with a capital letter designatevalues based upon The R.H.S. Colour Chart, published by The RoyalHorticultural Society, London, England.

The descriptive matter which follows pertains to 8 year old trees grownin the vicinity of Wasco, Kern County, Calif., during 2002, and isbelieved to apply to plants of the variety grown under similarconditions of soil and climate elsewhere.

TREE (Measurements Taken on an 8 Year Old Tree)

General:

Size.—Medium — normal for most plum varieties. Reaches a height ofapproximately 3-4 meters including normal pruning.

Vigor.—Vigorous; Growth of approximately 1.8 to 2 meters height thefirst growing season.

Growth.—Upright-spreading.

Productivity.—Productive. Fruit set is usually two or more times desiredamount for marketable size fruit. Thinning and spacing of fruit isnecessary.

Form.—Vase formed.

Fruit bearing.—Regular. No alternate bearing observed.

Fertility.—Somewhat self-fertile but pollinizer improves fruit set.

Density of foliage.—Dense. Pruning is required to open tree vase shape,allowing more sunlight to center of tree.

Hardiness.—Hardy in all fruit growing areas of California. Winterchilling requirement is approximately 650 hours at or below about 7.2°C.

Tree resistance/susceptibility.—No specific testing for relative plantdisease resistance/susceptibility has been designed. Under closeobservation in Kern County, Calif., no particular plant/fruit diseaseresistance/susceptibility has been observed.

Root stock.—Nemaguard.

Trunk: (Measurements at 30 cm above soil line).

Diameter.—Approximately 20 cm. Varies with soil type, fertility,climatic conditions and cultural practices.

Surface texture.—Medium shaggy, increases with age of tree.

Color.—About Greyed-orange 164B in recesses of the bark, and aboutGreyed-green 197A to Greyed-green 196A on the surface of the bark.Becomes darker with age.

Branches: (Measurements at 90 cm above soil line).

Diameter.—Ranges from approximately 8.0 cm to 9.0 cm.

Surface texture.—Smooth on 1st year wood, increasing roughness with treeage.

Color.—Branches are about Greyed-orange 164B in recesses of the bark,and about Greyed-green 197C to Greyed-green 198D on the surface of thebark.

Branch lenticels:

Number.—Absent.

LEAVES (Data Taken in July on Fully Expanded Leaf at Midpoint ofCurrent-Season Growth)

General:

Average length.—Approximately 90 mm.

Average width.—Approximately 35 mm.

Form.—Broadly elliptic.

Leaf blade tip.—Cuspidate.

Leaf base.—Rounded to cuneate.

Margin.—Strongly crenate.

Venation.—Pinnately net veined.

Leaf thickness.—Medium.

Color of upper surface.—About Green 139A.

Color of lower surface.—About Green 137C.

Surface texture.—Smooth.

Petiole:

Length.—Approximately 12 mm.

Diameter.—Approximately 1.5 mm.

Color.—About Green 138B.

Leaf Glands:

Average number.—Approximately 2.

Positioning.—Opposite on upper portion of petiole and base of leafblade.

Length.—Approximately 0.8 mm.

Width.—Approximately 0.8 mm.

Shape.—Globose.

Color.—About Greyed-orange 165A.

Stipules:

Number of stipules per bud.—Approximately 2.

Length.—Approximately 4 to 6 mm.

Flowering shoots: (Data taken in July at midpoint of current-seasongrowth).

Diameter.—Approximately 4 mm.

Color.—About Greyed-orange 165A.

Size.—Average.

Flowering shoot lenticels.—Plentiful.

Flowering shoot leaf buds:

Shape.—Ovoid.

Length.—Approximately 2 mm.

Width.—Approximately 2 mm.

Color.—About Greyed-orange 165A.

Flowering shoot flower buds:

Number per node.—Approximately 2 to 4.

Shape.—Ovoid.

Length.—Approximately 2 mm.

Width.—Approximately 2 mm.

Color.—About Greyed-orange 175B.

FLOWERS

General:

Date of first bloom.—Mar. 1, 2002.

Date of full bloom.—Mar. 4, 2002.

Size (diameter of the fully open flower).—Approximately 28 mm.

Flower aroma.—Very slight.

Peduncle:

Length.—Approximately 3 mm.

Diameter.—Approximately 1 mm.

Color.—About Yellow-green 145A.

Petals:

Number per flower.—5.

Arrangement.—Slightly overlapping.

Length.—Approximately 14 mm.

Width.—Approximately 12 mm.

Shape.—Circular.

Apex.—Rounded.

Base shape.—Narrows at point of attachment.

Color (fully opened flower).—White.

Surface texture.—Smooth.

Margins.—Smooth.

Sepals:

Number per flower.—5.

Length.—Approximately 4 mm.

Width.—Approximately 4 mm.

Shape.—Broad obovate.

Color.—About Yellow-green 145A to Yellow-green 144B.

Surface texture.—Smooth.

Stamens:

Number per flower.—Approximately 32 (typically ranges between 28 and34).

Length.—Approximately 7 mm.

Filament color.—White.

Anther color (just before dehiscence).—About Greyed-orange 168A.

Pollen color.—About Greyed-orange 168A.

Pistil:

Number of pistils per typical flower.—Usually one.

Frequency of supplementary pistils.—Occasionally two.

Pistil length.—Approximately 12 mm.

Pubescence.—None.

Ovary diameter.—Approximately 2 mm.

Stigma position in relation to anthers.—Stigma extends below anthers.

FRUIT

General: (Data taken at firm-ripe stage on mature tree managed to obtainmaximum quality under conditions stated above).

Harvest date of first pick.—Jun. 16, 2002.

Harvest date of last pick.—Jun. 26, 2002.

Length (stem end to apex).—Approximately 55 mm.

Diameter in line with suture plane.—Approximately 62 mm.

Diameter perpendicular to suture plane.—Approximately 65 mm.

Average weight.—Approximately 155 gm.

Shape viewed from apex.—Nearly rounded, symmetrical.

Shape viewed from side, facing suture.—Rounded, slightly flattened.Symmetrical.

Shape viewed from side, perpendicular to suture.—Rounded, slightlyflattened. Symmetrical.

Fruit apex shape.—Somewhat flattened.

Fruit stem-end cavity depth.—Shallow.

Stem:

Length.—Approximately 8 mm.

Diameter.—Approximately 2 mm.

Color.—About Green 143C.

Skin:

Thickness.—Medium.

Adherence to flesh.—Tenacious.

Surface texture.—Smooth.

Pubescence.—None.

Bloom.—Moderate amount.

Ground color.—Does not show.

Overcolor.—About Greyed-purple 187A, becoming black as fruit ripens.

Taste.—Neutral.

Flesh:

Color.—About Red 36D, becoming about Red 43A from perimeter toward pitcavity as fruit ripens.

Texture.—Fine textured and firm.

Ripens.—Evenly.

Fibers.—Few.

Flavor.—Bland-sweet to sweet.

Aroma.—Moderate.

Brix.—Approximately 18 degrees.

Juice.—Plentiful.

Use.—Dessert market, local and long distance.

Keeping and shipping quality.—Good. Holds well in cold storage forapproximately 6 weeks and maintains good firmness and eating quality.Minimal bruising and scarring in packing and shipping trials.

STONE (Measurement Taken on Dried Stones)

General:

Adherence to flesh.—Clingstone.

Length.—Approximately 21 mm.

Diameter in line with suture plane.—Approximately 18 mm.

Diameter perpendicular to suture plane.—Approximately 8 mm.

Form (viewed from broad side).—Obovate. Asymmetrical because ofoutgrowing keel.

Form (viewed from stem end).—Oval, symmetrical. Becomes narrow on oneside because of outgrowing keel.

Base shape.—Flattened to slightly rounded. Retuse at stem attachment.

Apex shape.—Rounded with a small dull point.

Stone surface.—Irregularly furrowed throughout; heavily ridgedthroughout; lightly pitted throughout.

Comparison of stone halves.—Nearly equal.

Ridges.—One on each side of the suture, well formed, sharp, beginning atthe base and extending throughout the length of the stone.

Stone outgrowing keel.—Well developed.

Tendency to split.—None.

Stone color when dried.—About Greyed-yellow 161C.

What is claimed is:
 1. A new and distinct plum tree named‘Suplumtwentyeight’ as herein described and illustrated.